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United States Science

NYC Is Sinking Due To Weight of Its Skyscrapers, New Research Finds (theguardian.com) 94

New research reveals that New York City is sinking, primarily due to the weight of its tall buildings, exacerbating the threat of flooding from rising sea levels. The Guardian reports: The Big Apple may be the city that never sleeps but it is a city that certainly sinks, subsiding by approximately 1-2mm each year on average, with some areas of New York City plunging at double this rate, according to researchers. This sinking is exacerbating the impact of sea level rise which is accelerating at around twice the global average as the world's glaciers melt away and seawater expands due to global heating. The water that flanks New York City has risen by about 9in, or 22cm, since 1950 and major flooding events from storms could be up to four times more frequent than now by the end of the century due to the combination of sea level rise and hurricanes strengthened by climate change.

This trend is being magnified by the sheer bulk of New York City's built infrastructure. The researchers calculated that the city's structures, which include the famous Empire State Building and Chrysler Building, weigh a total of 1.68tn lbs, which is roughly equivalent to the weight of 140 million elephants. This enormous heft is pushing down on a jumble of different materials found in New York City's ground. While many of the largest buildings are placed upon solid bedrock, such as schist, there is a mixture of other sands and clays that have been build over, adding to a sinking effect that is naturally occurring anyway along much of the US east coast as the land reacts to the retreat of huge glaciers following the end of the last ice age.
The research has been published in the journal Earth's Future.
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NYC Is Sinking Due To Weight of Its Skyscrapers, New Research Finds

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  • by omnichad ( 1198475 ) on Saturday May 20, 2023 @05:07AM (#63536823) Homepage

    a mixture of other sands and clays that have been build over

    Sands and clays thrown on top of old landfills, you mean. Canal Street was literally the drainage ditch to extract water from a landfill as it was being packed down with topsoil to build on. Manhattan has grown significantly in size during its history in almost every direction and has basically involved throwing trash in the water and then building on top of it.

    Besides just the edges, the island used to be full of creeks and streams, which - after serving as a primitive sewer system was also filled in for building on.

    • Given enough time all cities are kind of like this. Many of the oldest european cities are city ontop of city ontop of city for layers. And lets not delude ourselves, long after we are forgotten, our cities will be under rubble too, with luck a newer incarnation built over the top. Assuming we solve climate change, dont nuke ourselves, and the robots dont decide to do something very incompatible with humans, ETC.

    • Re: (Score:1, Flamebait)

      by quonset ( 4839537 )

      Canal Street was literally the drainage ditch to extract water from a landfill as it was being packed down with topsoil to build on.

      How about just for draining what was there since the land was unusable [narratively.com].

      Cattle that set out in the surrounding fields were sometimes lost in the “pestilential quagmires” around them. One nineteenth-century writer told of a man, lost in the dark, who drowned in deep water at what is now the intersection of Grand and Greene Streets—smack in the heart of SoHo.

      The marshland was unusable for the earliest settlers, so in the 1730s the King of England granted ownership of the area to a landowner named Anthony Rutgers on the condition that he drain it. Over the next few decades, Rutgers and his son-in-law dug a drainage ditch through the middle of the marsh, and this ditch became the predecessor of present-day Canal Street.

      Besides just the edges, the island used to be full of creeks and streams, which - after serving as a primitive sewer system was also filled in for building on.

      In addition to pestilence and genocide, the Europeans brought their way of doing things to the continent. London used to have a multitude of rivers

      • by Okian Warrior ( 537106 ) on Saturday May 20, 2023 @10:38AM (#63537237) Homepage Journal

        In addition to pestilence and genocide, the Europeans brought their way of doing things to the continent.

        And got tobacco and syphilis in return.

        Also, the European way of doing things allows for the creation of wealth, which eventually leads to a higher standard of living that includes things like better nutrition, medical treatment, and sanitary practices. Also, a rights-based legal system: it's estimated that 40% of all adults in hunter gather society die by violence - tribes making war on each other, constantly acting out blood feuds and revenge killings.

        This constant dislike of everything Western is simply not correct, and probably funded by Chinese interests.

        • > Also, the European way of doing things allows for the creation of wealth, which eventually leads to a higher standard of living that includes things like better nutrition, medical treatment, and sanitary practices.

          But is that saying much more that the "European Way" is a thing.

          If you said cooperation brought us ... then I'd agree. That's a human thing.

          > Also, a rights-based legal system: it's estimated that 40% of all adults in hunter gather society die by violence - tribes making war on each other,

          • Pretty sure its not funded by Chinese interests. Their own past reflects much of the same issues with Europe's past.

            People denigrating European imperialism are doing so because it is the only thing they know. Most people in the United states are not taught anything about Chinese history. They learn about England, France, Spain, and Italy for the most part. They absolutely committed a lot of atrocities and its not a bad thing to review that and understand that society can indeed continue to improve. This re

            • > Pretty sure its not funded by Chinese interests. Their own past reflects much of the same issues with Europe's past.

              Agreed.

              What I wrote wasn't very clear.

              Okian Warrior wrote "Also, the European way of doing things allows for the creation of wealth, which eventually leads to a higher standard of living that includes things like better nutrition, medical treatment, and sanitary practices."

              What I was trying to say was that It makes as much sense to look at things and say "the European way of doing things

    • by YetAnotherDrew ( 664604 ) on Saturday May 20, 2023 @06:32AM (#63536945)

      Besides just the edges, the island used to be full of creeks and streams, which - after serving as a primitive sewer system was also filled in for building on.

      Central Park was built on a swamp. Which meant only poor people lived there. In the century before communities were displaced with highways, NY created parks instead.

      https://www.centralpark.com/visitor-info/park-history/overview/ [centralpark.com]

    • The authors' model is based on New York City's land being composed of surface minerals all the way down. Well, that's not how geology works. The are different strata as you go deeper. It's a terrible (lazy) premise and the authors: Tom Parsons, Pei-Chin Wu, Meng (Matt) Wei, Steven D'Hondt, should be ashamed of their flamebait paper.

    • by arQon ( 447508 )

      When I lived in Battery Park, there were maps posted there showing how much of Manhattan was "reclaimed" land, and it's genuinely impressive. The most expensive real estate in the world, literally built on trash. :)

      (Insert MS / Google / Amazon joke here...)

  • One of the bridge caissons didn't make it all the way down to bedrock, they were having such a hard time they gave up. They had no idea about nitrogen bubbles in their veins. https://www.youtube.com/watch?... [youtube.com]

    • Yep. The cause of Caisson's disease (decompression/diving sickness) was actually discovered in St. Louis during the building of another bridge. Which was what inspired the design of the Brooklyn Bridge. Too bad the first bridge wasn't finished yet when they started the technique or they would have known how to avoid it.

      https://www.pbs.org/wgbh/ameri... [pbs.org]

  • by monkeyxpress ( 4016725 ) on Saturday May 20, 2023 @05:23AM (#63536839)

    How does stating the weight of all the structures in elephant equivalent units help me understand the situation? I mean, the whole idea of comparative units is to give a sense of comparable scale, but elephants are tiny compared to most buildings.

    In any event, the land area of manhattan is apparently around 60 million square metres, so this means there would be 0.4 square metres per elephant. I'd estimate a closely packed elephant takes up about 2-3 square metres, so this is an elephant density of about 5-6 elephants stacked on top of each other.

    I guess if you liquidized the elephants, they would take up about half this space, so you're talking a pool of elephant sludge maybe a couple metres deep.

    As to whether this is an excessive number of elephants for manhattan island to deal with I have no idea.

    • by omnichad ( 1198475 ) on Saturday May 20, 2023 @05:30AM (#63536853) Homepage

      Discworld units. Writers must be flat-earthers and know approximately how many elephants are needed on the back of a turtle to support the weight.

    • by Latent Heat ( 558884 ) on Saturday May 20, 2023 @06:32AM (#63536947)

      It's elephants, all the way up!

    • by dskoll ( 99328 )

      Yeah, 140 million elephants is meaningless. Now, if they'd have expressed it in the weight of football fields, Americans would have instantly understood it.

    • How does stating the weight of all the structures in elephant equivalent units help me understand the situation? I mean, the whole idea of comparative units is to give a sense of comparable scale, but elephants are tiny compared to most buildings.

      We’ll ask them to use Libraries of Congress next time.

    • If you used all the elephants in existence, the elephant sludge wouldn't even be ankle deep. 140 million elephants is about 300 times the world's population of them
    • by bosef1 ( 208943 )

      "I guess if you liquidized the elephants..."

      Your ideas are intriguing to me, and I wish to subscribe to your newsletter.

    • I agree, also they didn't specify African Bush(2,160-6,000kg max 10,400kg), African Forest(up to 4,000kg) or Asian/Indian elephant(2,700-4,000kg max 7,000kg).
      Given that 1.68tn lbs=760*10^9kg they have used 760*10^9/140*10^6=5,429kg as the weight of an elephant. So I guess they are mostly male African Bush elephants.

      I don't think they specified Manhattan but all of New York city which is 778km^2. African elephants are 3-5m long and 1.3-2.1m wide using the max values to allow a bit of space that is 5*2.1=10.2

      • by Askmum ( 1038780 )

        Given that 1.68tn lbs

        I'm still at a loss wat "tn" should be. My first gues would have been ton, which is 1000 kg or 2200 lbs, but from the off that would be way to small. Calculating back from the average weight of an elephant and the pound I did arrive at 10^12, or tera. How is tera being abbreviated to tn?

        So I'm right in thinking the 1.68tn lbs = 3.7x10^12 kg or 3.7 Eg (Exagram)?

    • by tlhIngan ( 30335 ) <slashdot@worf.ERDOSnet minus math_god> on Saturday May 20, 2023 @03:16PM (#63537825)

      The problem isn't the elephants, it's the quantity.

      140 million anythings is a number that a human can't comprehend.

      My old physics teacher did a day on "people units" - how to relate things that people could understand. Kilograms and such, they're easy to understand. But give a length like a million millimeters, you can't. Even reduce it down to 1000 kilometers, it's still somewhat vacuous - is that a day's drive? two day's drive? what? People cannot relate that kind of distance.

      So reduce it - if you drive at 100 kph, which is an average highway speed, that's a 10 hour drive. OK, now you have a relation people can understand - it's basically an all day road trip where you get up at 5AM in the morning and know you won't arrive until around 8PM that day (time for breakfast, lunch, dinner fuel stops, pee stops, and breaks to stretch the legs).

      Sure, it isn't perfect - I mean, you converted a length to a time, but you'll find people can relate more to the distance based on the time of long road trips than they could as just a length. If you don't do road trips, it's about a 3 hour flight.

      That's "people units". Comparing something to an elephant? OK, you can do it for rough scale. But 140 million elephants is just as senseless a unit as the actual weight in kilograms or pounds or whatever. It's meaningless - the human mind cannot comprehend 140 million anythings. 1.68 trillion pounds... that is just as good as 140 million elephants. Both are numbers no human has a sense of scale with.

      Maybe ... an olympic sized swimming pool holds 2.5 million litres of water, which assuming standard convertsions, is about 2.5 millions kilograms.. That's still over 300k swimming pools.

      How about cruise ships? Wonder of the Seas, the world's largest cruise ship, has a weight of about 237,000 tons (not tonne), so New York weigns just over 3500 cruise ships. We're getting there, but it's still not perfect.

      That's what providing numbers in people sized units is about - it's trying to create a number that conveys the scale that can be imagined. I just can't think of anything heavier. The goal is to relate a number to something people would have in ordinary experiences.

      That said, I think I can probably imagine 3500 cruise ships a bot better than 140 million elephants.

    • More importantly: African elephants or Indian elephants?

    • How does stating the weight of all the structures in elephant equivalent units help me understand the situation?

      I agree, I had to multiply by 2.9m to convert to cicada equivalent units before it made sense.

  • What is "1.68tn lbs"?

    American units of measurement on overdrive, methinks.

    Google didn't help. Can someone translate into "normal", please? (i.e. metric)

    • Re: (Score:3, Informative)

      by omnichad ( 1198475 )

      840 million US Tons or 762 million Metric Tons.

      Using pounds is about the dumbest idea since there are units a few orders of magnitude closer to the right scale. It's not like Kilograms would make any more sense.

      • > It's not like Kilograms would make any more sense.

        Why don't I ever hear 'gigagrams'? These SI people don't really seem to internalize it.

        • SI people are weenies if they don't also adopt the metric calendar.

          https://en.wikipedia.org/wiki/... [wikipedia.org]

          I especially like the French Republican Calendar girls -- Madmoiselle Thermidor is my fave.

        • I have seen megagrams on a paper, obviously not an American one.

          The most sensible unit is the nautical mile. One minute of longitude at the equator.

          One calorie to heat one gram of water one degree C makes sense, as does one BTU to heat one pound of water (which is also one pint) one degree F.

          On the other hand the Pascal is the dumbest unit, as in least practical unit. 101300 of them to make sea level pressure? Really?

          • by dryeo ( 100693 )

            The metre was originally one ten millionth of the distance from the equator to the north pole. 40,000 km circumference. And then it had the same problem as the nautical mile, the world is not a sphere
            A pint does not weigh a pound. A gallon is defined as 10 lbs of water (at 50f IIRC) containing 160 fl oz. A pint is 20 fl oz or a pound and a quarter so a BTU is an odd measure.
            It's the problem with customary units, which custom?

        • by rossdee ( 243626 )

          Yeah they should drop the unit "tonne" and use megagram instead..

          For large masses, use n x 10^m grams, (where m is a multiple of 3)

      • 840 million US Tons or 762 million Metric Tons.

        Using pounds is about the dumbest idea since there are units a few orders of magnitude closer to the right scale. It's not like Kilograms would make any more sense.

        It would weigh a lot less if they used British Pounds.

      • 1 tonne = 1000 kg

        A tonne isn't an SI unit, but is accepted for use in SI.

        So you've already given the answer in kg, effectively.

        Thank you.

    • by fazig ( 2909523 )
      The "tn" is the abbreviation for trillion that is used in the UK according to https://www.antidote.info/en/b... [antidote.info].
      Yes, this time it's not weird American units, it's weird UK units.
      • That's so you don't confuse with just "t" which is tons / tonnes and has been for centuries. Don't blame others who had the perspicacity to differentiate when you can't be bothered to write the additional letter.

    • What is "1.68tn lbs"? American units of measurement on overdrive, methinks.

      Didn't you see they provided a helpful equivalent in standard Hannibal elephants ?

      • Well, they didn't specify "standard Hannibal", so I was left wondering if they used the UK "Asian elephant" or the US "American elephant".

        Or is it the other way around?

        • I presume Hannibal used African Elephants, since Carthage is in Africa.

          However I think they would have lost a bit of weight while crossing the alps.

    • They did convert it to elephants. What else do we need!?

  • "Weight" is a measurement of the force created by the action of a gravitational field upon mass
    • All we have to do is get the planet spinning fast enough, and then the buildings won't weigh so much

      • by ffkom ( 3519199 )

        All we have to do is get the planet spinning fast enough, and then the buildings won't weigh so much

        That plan has a minor problem: The sea water level would also bulge / rise due to the faster spinning. So a better idea may be to change the spinning axis of Earth such that New York is at a pole. Let's not bother ourselves with thinking about side-effects of this. :-)

    • Re:In other news (Score:4, Informative)

      by Anubis IV ( 1279820 ) on Saturday May 20, 2023 @07:17AM (#63536993)

      Weight is also the unit that is relevant here, given that we are talking about the effects of the force on the ground beneath the buildings.

    • by dfm3 ( 830843 )
      Well if not for the force of gravity, all the mass of those skyscrapers wouldn't be moving toward the center of the earth. ;-) I'm not sure if you're trying to be pedantic, but technically they're not wrong. It's like saying, "my car is moving in this direction due to acceleration."
    • It's the weight and not the mass that's the issue here. So, for once, weight is correct.

  • Between when New York City will be underwater vs when the State of Florida will be. Either way millions lose.

    • by Anonymous Coward

      Its not as if Florida would be a great loss.

    • Don't bring race into this very important debate please.

    • Between when New York City will be underwater vs when the State of Florida will be. Either way millions lose.

      Yes, hundreds of millions lose when floridians and new yorkers show up to tell them how great their states were, and start voting.

    • If Florida goes underwater, where will retired New Yorkers live in the winter?

      (Kinda not kidding. “Snowbirds” from places like New York cause Florida’s population to temporarily swell by about 5% every winter. At the time that I left Florida, well over 20 years ago now, the font sizes of all signage on intersections in my area was being bumped up significantly to deal with the growing presence of people with poor vision on the road.)

      • I have been to Florida exactly once. There were many billboards. They advertised plastic surgery, injury and malpractice law, and mortuary services. My Tampa hotel lobby had an inch of water on the floor. The only argument against letting or making the state drown immediately, is the prospect of half of Trump being found in a ditch next to an alligator with terminal indigestion.
    • The race won't be over until Boston is on fire. But I'll call it a draw.

  • The land tends to rebound at 1, World Trade Center.

  • Of all the things you could worry about, you choose this?

    • Four inches is the low end (if it sinks 1mm/year). The high end (for the faster sinking regions) would be nearly 16 inches, and that's before you account for the sea level rising to meet it. It's an island; there's quite a lot of it that will be underwater on the regular if the combined effect of sea level rise and sinking puts it three feet lower.
  • by chas.williams ( 6256556 ) on Saturday May 20, 2023 @07:42AM (#63537021)
    That would help, right?
  • It does not get much more obvious than this one. The oversized palace is dragging itself down to be drowned.

  • Penthouse (Score:4, Insightful)

    by sprins ( 717461 ) on Saturday May 20, 2023 @08:50AM (#63537103)

    That's why you want the penthouse appartment.

  • It is a beautiful state(at least the imprisoned upstate area is). But with crazy in charge of the city and thus the state, again! There is no hope for the state.
  • Wait! What? (Score:3, Informative)

    by PPH ( 736903 ) on Saturday May 20, 2023 @10:41AM (#63537243)

    adding to a sinking effect that is naturally occurring anyway along much of the US east coast as the land reacts to the retreat of huge glaciers following the end of the last ice age.

    We have a similar process going on here in Washington state. Glaciers melting. But the result is that the land is rebounding [wikipedia.org] due to the weight removal. And the local sea level (relative to the land) is dropping. As the above linked page shows, this phenomenon appears to be prevelant in Northern continental areas with the exception of a region off the East coast. Which is sinking. So, the explanation for NYC could be geologically more complex. In general, the average crust is sinking across most of the globe. So I'm sure someone will point out the inequity of such geological processes in terms of white Northern Europeans vis a vis people of color elsewhere.

  • they better raise their streets by 1 meter every 1000 years or so.
  • something fishy (Score:2, Informative)

    by groobly ( 6155920 )

    I don't doubt there is significant subsidence in Manhattan, but I fail to believe it is because of skyscrapers. Skyscrapers are built on bedrock, and the shallowness of bedrock in Manhattan is what enabled skyscrapers in the first place. (Note SF's issue with Millenium Tower, which they allowed to NOT be anchored on bedrock.)

    I would also suggest that "rising sea levels" around NYC are not accelerating at all from historical rates, but are having only an apparent increase due to subsidence.

    • There is an article on ny.curbed.com [curbed.com] showing the Jacques Cortelyou map of southern Manhattan from 1660 overlaid on the current map of Manhattan. Southern Manhattan has easily doubled in size since the Cortelyou map was made, and for all that there may be bedrock under there, the land itself is all landfill.
  • by ffkom ( 3519199 ) on Saturday May 20, 2023 @11:48AM (#63537353)
    Move the stuff from the current ground level to the new top floor. Wait for the water to turn the streets into canals. Rename "New York" to "New Venice", then ask tourists for a premium for the transport in Gondolas. Relabel the subway tunnels as "Cenotes", and ask tourists a premium for swimming or diving there.
    • For the buildings sitting on bedrock, that might be a solution of sorts. If you can figure out how to protect the building from harm from water inundation, you could just sort of scoot up the building. The problem is, some of those buildings are right next to tall buildings not sitting on bedrock, and those are going to be a problem. Also, they are going to need some kind of seawall to break waves, so they don't break on buildings. They won't hold up to that for long.

      The subways are of course screwed, your

  • Not fast enough.
  • by Fons_de_spons ( 1311177 ) on Saturday May 20, 2023 @03:21PM (#63537843)
    So... New York will not be wiped away by giant UFO's on independence day.
    Godzilla will not wipe away it's buildings.
    It will not get burned by massive solar flares, meteors,...
    It will just s-l-o-w-l-y sink away. Now that is one hell of a boring disaster movie.
  • Harris County (Houston) maps subsidence. https://www.arcgis.com/home/we... [arcgis.com]

    It's clear from that map that subsidence has nothing to do with the weight of buildings. The Central Business District, where the skyscrapers are clustered, has a very low rate of subsidence. The highest rates are in far-flung suburbs, where there is nothing but low-rise buildings. Rather than blaming heavy buildings, in Houston, subsidence is caused by overuse of underground aquifers.

    I'd be interested in seeing a similar map of NYC,

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